Would like some help with regards to speedy clear caseback, I understand that with third party casebacks, there is a need for a spacer ring to hold the movement down, however would it be the same if say i were to switch a 1863 caseback (left) over to my 321 (right), seems like the spacer ring is too thick for the caseback to screw on. Is there a need to have a spacer say if i should (theoretically) do that?

 

There are different movement spacers, called enlargement rings by Omega. The sapphire case back models have a different enlargement ring compared to the normal steel back version. Also the 321 movement uses a different enlargement ring compared to the 861/1861 models.

For the third party case back, which you have on the 321 in the photo, you have the standard 321 enlargement ring and then the third party spacer ring. The third party spacer ring will hold the movement firmly in the case once the sapphire case back is installed. The steel case back models use the magnetic shield to hold the movement firmly in place once the case back is screwed down.

 

thanks for your reply! so based on what you said if i were to transplant the caseback from my 3572.50, I would need a different kind of spacer ring from the third party one?

 

The 3rd party spacer just sits on top of the original 321 enlargement ring. The 3572.50 has a different design enlargement ring from both the standard 861/1861 and the 321. Although the internal case sizes are the same, the 321 enlargement ring has holes for the pusher actuators (and stem) whereas the 1863 enlargement ring has slots for the pushers. This means the enlargement ring for the 861/1861/1863 can be removed without removing the movement from the case but for the 321 you have to remove the movement in order to remove the enlargement ring from it.

I think 321 enlargement ring has holes instead of slots because the holes are designed to keep the pusher actuators in place, the 1863 movement has a different design.

So to answer your question, yes you would need a different design enlargement ring. Possibly the same as the 1863 enlargement ring but with holes instead of the slots, it might be possible to use the 1863 enlargement ring but I've never tried it on mine.

 

thanks for the great insight! any idea where i could find an enlargement ring for the 321 movement?